Issue: Jan 2005


Definitely Not the New Cavalier



A solid foundation and focus on quality takes the Chevrolet Cobalt to a new level in the small car market.

by Gary Witzenburg

Forget everything you ever knew about Chevrolet’s long-running Cavalier subcompact. Cobalt may succeed it historically, but it is architecturally unrelated and vastly superior in every conceivable way.









 
Cobalt comes in two flavors, a sedan and a uniquely-styled coupe.
 
With the Korean-built Aveo (from GM’s Asian arm, formerly known as Daewoo) assuming Chevy’s entry-level role, Cobalt moves a notch up in price and way upmarket in quality.

The engineering team’s orders from GM Vice Chairman Bob Lutz and small car Vehicle Line Executive Lori Queen was to design and develop the best car in class. Really! “We wanted to bring a credible small car back to Chevy in a really big way,” Queen says. Taking that order seriously, they drew up a wish-list of 150 components, systems and attributes required to achieve that … and were thrilled and surprised to see those wishes granted.

“We benchmarked all our competitors,” she relates. “We had to lead in NVH [noise, vibration and harshness] and achieve best-inclass body gaps. On our very first evaluation drive of prototypes, the Cobalt exceeded all the targets when judged against the list of competitive vehicles’ strengths and market advantages. The 150-point list was a sort of Holy Grail on which the engineers focused their attention. And with such strong results, there was no going back. There truly were no compromises to the list.”

“What has Cobalt in common with Cavalier? Other than its Ecotec engine, transmission and basic suspension layout — essentially nothing. The suspension geometry is all different,” GM Small Car Program Engineering Manager Gary Altman asserts. “The whole setup and how it performs. The lower control arms have additional ride bushings of an elastomeric that can dampen itself yet be soft. The rear axle is designed, mounted and controlled completely differently, similar to that on GM’s European Opels, with special bushings and the attitude [fore-aft angle] of its trailing arms enabling precise tuning of its handling response. The EPS (electronic power steering) is vastly improved over the Saturn’s, yet retains the fuel economy benefit. The interior [by Intier] and the way it’s put together are significantly different, with European accent and Chevy brand character. The concept is that fewer pieces are better.”







 
Cobalt’s interior is clean, comfortable and well constructed.
GM’s robust Delta architecture (updated and improved over the original Saturn Ion’s) is the foundation for Cobalt’s surprisingly solid feel. Its stiff structure allowed engineers to tune the MacPherson-strut front and twist-beam rear suspension with long wheel travel and directacting components without having to compromise for chassis flex. “It allowed us to work with other components independently to optimize ride and handling and NVH,” Altman says. “The Delta architecture represents a culmination of people we brought together from GM Europe, Latin America and our Asia- Pacific region,” he explains. “It’s a global architecture designed for global requirements using a lower dominant structure concept. From the front bumper and tie bar, each rail transitions into two separate rails through the underbody, then comes back together into a single rail going out the rear of the car. By developing that lower structure to handle all the load inputs, we’re able to increase stiffness in both torsion and bending so we don’t depend on the upper structure as much as in the past.

“Because the car can sustain itself on the lower part of its structure, you don’t need hydraulic motor mounts or absorbers compensating for body inputs that are amplifying road inputs. You can deal with them specifically, which makes the job much easier, and get to a higher level of performance.” The stiff structure (28 Hz average bending and torsional stiffness) also enables precise exterior tolerances, while a one-piece body side stamping reduces assembly line variation. The engineers point proudly to Cobalt’s windshield and backlight, installed with exposed-edge glass instead of conventional sealing frames, a visual testament to a level of precise build quality uncommon in the segment.







 
The dash lacks a temperature gauge, which GM says is no longer a necessity as today’s electronically controlled engines don’t overheat.
“This architecture conceptually started with discussions a long time ago when we had the idea that we should consolidate engineering homerooms,” Altman continues. “But at that point it wasn’t really an architecture. It was a discussion of, ‘What are the benefits of consolidating engineering resources and technologies in the development of a car?’” The Delta’s engineering design process began in 1998, and it debuted with the ’02 ION in 2001.

“This is one of the first vehicles where we used a lot of virtual analysis and development, and one of the first where probably more than 50 percent of our engineers were also designers. They literally did component level analysis, design and engineering of their own parts on unigraphic models in what we call “big collaboration rooms” on four-by-six-foot screens, and communicating with other rooms at other locations, including key suppliers.

“We were even able to do regular virtual builds during design and development. We pulled parts together and did interface and interference checking, workplace simulations, tool clearances and assembly plant throughput calculations.” From Vehicle Program Initiation (VPI) to SOP (Start of Production), the sedan took 21 months and the coupe 18 months.

“And there have been significant changes in the assembly operation, including doors-off processing and a completely different body shop. It’s a complete new modern assembly process, and all these changes were done while the J-car was running. We literally turned off the J-car one day and had seven days to turn on the Cobalt full-time,” Altman says.

Cobalt is offered in two body styles with very different characters — conservative sedan and expressive coupe with Corvette-like quad round taillamps — in base, LS and uplevel LT trim. The star of the line is a delightfully agile and quick SS Supercharged coupe with GM’s 205-hp 2.0L Eaton-boosted Ecotec, FGP 5- speed manual, sport suspension, four-wheel discs with ABS, 18-inch performance wheels and tires, specific front and rear fascias and interior appointments, including an A-pillar-mounted boost gauge, and a wild (and rear-vision-impairing) rear wing.







 
 GM’s global Delta platform is the basis for the Cobalt. A stronger, stiffer lower structure has increased torsional stiffness so designers don’t have to rely on the upper body to carry as much of the load.
Standard powertrain is GM’s lively 145-hp, 155-lb.ft. 2.2L DOHC, 16- valve Ecotec with electronic throttle control and numerous long-life and maintenance-free features. A 170-hp version will follow soon. Available transmissions are standard Getrag 5-speed manual or optional Hydra- Matic 4T45E electronically controlled 4-speed automatic. Enhanced traction control, standard on automatic Cobalts with ABS, improves low-traction performance by detecting wheel slip and adjusting engine torque to limit slip-inducing power. EPA economy is 23 mpg city/29 highway manual, 24/32 automatic and a surprising 25/34 supercharged.

Prices start at $14,190 for the base coupe and sedan, $18,760 for the LT sedan and $21,995 for the SS Supercharged coupe. All come with a list of standard features including air conditioning, electric rear defogger, CD player, driver information center and a split-bench rear seat with a pass-through to the trunk area.

Okay, the back seats are subcompact tight, and there’s no temperature gauge (Altman says temp gauges aren’t very accurate anyway, and sophisticated engine electronics prevent overheating damage), but Chevy’s new Cobalt is amazingly quiet, solid and satisfying for its size and price. And better than, or at least fully competitive with, everything else in its class.

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